Introduction

The NES has a slightly modified version of the MOS 6502 CPU. This CPU was quite popular back in the day so there is plenty of detailed documentation about it online.

Terminology

We won’t be using any fancy emulation/NES terminology here, just basic computer stuff. I will explain some terms very simply, if you want a more in depth explanation you can look these things up online.

• Registers - small and fast areas of storage the CPU can fetch data from and write data to.